Several attempts have been made in the prior art to automatically ventilate a vehicle or an enclosed space. One such system is described in U.S. Pat. No. 4,852,469 for an "Automatic Venting System" issued to Chuang, and incorporated herein by reference. The system accomplishes ventilation by opening one or more of the vehicle vents, eg. the windows, sun roof or convertible top, when the temperature inside the vehicle is higher than a desired level. In addition, if precipitation is sensed, the system automatically shuts the open vents. U.S. Pat. No. 5,054,686 for an "Automobile Environment Management System" also issued to Chuang, and incorporated herein by reference, discloses further improvements to the automatic venting system, and includes safety features such as passive infra-red living being detection.
Unfortunately, the prior art systems operate so as to close the open vents of the vehicle in response to a predetermined condition, such as precipitation detection, regardless of whether or not the vehicle is occupied. Accordingly, if a child, pet or other living being remains in the vehicle and accidently places their fingers, arm or other objects in the vents opening space during the closing operation, unacceptable injury or damage may occur.
Conventional vent closing systems provide various approaches to solving safety problems during vehicle ventilation closing operations. However, due to the technology limitations, the conventional systems are either not adequate to provide safety security or too cumbersome and expensive to be installed and operated, or both. Typically, this is due to the use of a system involving the comparison of operating currents to fixed thresholds or simply detecting an occurrence of a motor stall current level.